/Engine/Source/Runtime/Engine/Classes/Components/SkeletalMeshComponent.h
Enables or disables gravity to all bodies below the given bone. NAME_None indicates all bodies will be edited. In that case, consider using UPrimitiveComponent::EnableGravity.
void SetEnableGravityOnAllBodiesBelow ( bool bEnableGravity, [FName](API\Runtime\Core\UObject\FName) BoneName, bool bIncludeSelf )